Brain Structure and Function

, Volume 223, Issue 4, pp 1881–1895 | Cite as

Changes in neocortical and hippocampal microglial cells during hibernation

  • Gonzalo León-Espinosa
  • Mamen Regalado-Reyes
  • Javier DeFelipe
  • Alberto Muñoz
Original Article


Mammalian hibernation proceeds alongside a wide range of complex brain adaptive changes that appear to protect the brain from extreme hypoxia and hypothermia. Using immunofluorescence, confocal microscopy, quantitative analysis methods and intracellular injections, we have characterized microglia morphological changes that occur in the neocortex and hippocampus of the Syrian hamster during hibernation. In euthermic hamsters, microglial cells showed the typical ramified/resting morphology with multiple long, thin and highly-branched processes homogeneously immunostained for Iba-1. However, during torpor, microglial cell process numbers increase significantly accompanied by a shortening of the Iba-1 immunoreactive processes, which show a fragmented appearance. Adaptative changes of microglial cells during torpor coursed with no expression of microglial cell activation markers. We discuss the possibility that these morphological changes may contribute to neuronal damage prevention during hibernation.


Resting microglia Activated microglia Dystrophic microglia Syrian hamster Torpor Iba-1 



This work was supported by grants from the following entities: SAF 2015-66603-P from the Ministerio de Economía y Competitividad; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas (CIBERNED, CB06/05/0066, Spain); and a grant from the Alzheimer’s Association (ZEN-15-321663). We thank Soledad Martínez for technical help with the surgical procedures in middle cerebral artery occlusion experiments and Natalia Yanguas for providing antibodies for CD16/32 and CD64.

Compliance with ethical standards

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that should be construed as a potential conflict of interest.

Ethical approval

All experimental procedures were carried out at the animal facility in the San Pablo CEU University of Madrid (SVA-CEU.USP, Registration Number ES 28022 0000015) and were approved by the institutional Animal Experiment Ethics Committee.


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© Springer-Verlag GmbH Germany, part of Springer Nature 2017

Authors and Affiliations

  1. 1.Instituto Cajal, CSICMadridSpain
  2. 2.Laboratorio Cajal de Circuitos Corticales (CTB), Centro de Tecnología BiomédicaUniversidad Politécnica de MadridMadridSpain
  3. 3.CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades NeurodegenerativasMadridSpain
  4. 4.Departamento de Biología CelularUniversidad Complutense ComplutenseMadridSpain
  5. 5.Facultad de FarmaciaUniversidad San Pablo CEUMadridSpain

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